It is known that heteropolysaccharides can be produced by certain microorganisms. These heteropolysaccharides can function as hydrophilic colloids, and, because of their rheological properties, have been used as thickening and gelling agents for aqueous systems.
Kang et al., U.S. Pat. No. 4,326,053, describes a heteropolysaccharide, gellan gum, prepared by fermentation of Pseudomones elodea ATCC 31461, which is useful as a thickening, suspending and stabilizing agent in aqueous systems. The patent also describes a deacylated heteropolysaccharide useful as an agar substitute and for forming rigid, brittle gels. Kang et al., U.S. Pat. No. 4,326,052, describes a clarified deacylated heteropolysaccharide obtained by subjecting the deacylated heteropolysaccharide of U.S. Pat. No. 4,326,053 to filtration, and subsequently adding filtrate to isopropanol, and drying and milling to obtain clarified heteropolysaccharide with low levels of protein.